Question: Which chemical element of subclass period 5 has the highest density?
Paraphrase: What is the densest element in subclass period 5?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q11344 . ?ent wdt:P2054 ?obj . ?ent wdt:P279 wd:Q244982 } ORDER BY DESC(?obj)LIMIT 5 
Answer: rhodium, silver, molybdenum, cadmium, Indium